Lore: Sabbat covers knowledge about the oppositional sect known as the Sabbat, those who intend to destroy the Camarilla and - so they think - end the threat from the Ancients by so doing. Knowledge of this information by a non-Sabbat is considered by most Sabbat to be a signed and sealed death sentence.
What a fledgling Sabbat who had survived their Rites and initial nights is likely to know. This includes some of the terminology to use and some of the hand signs, and likely how to learn new ones as well, and the enmity between Sabbat & Camarilla. The clans and disciplines native to the Sabbat are familiar terms, and the enmity has been given depth and shape. Ritae have been taught/learned. You could talk with a member of the group in question without giving yourself away - maybe. Most True Sabbat should have at least this level. You've learned things you wish you never had. At this stage, you begin hearing about rumors and secrets and bits of history that others would prefer be left alone. You know the subjects at least as good as they know themselves. This could well be terminally dangerous, given the desire of certain branches of the sect to remain as secretive as they can.